4.9-stable review patch. If anyone has any objections, please let me know.
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From: Vasily Averin vvs@virtuozzo.com
commit 3a2b19d1ee5633f76ae8a88da7bc039a5d1732aa upstream.
Commit efda760fe95ea ("lockd: fix lockd shutdown race") is incorrect, it removes lockd_manager and disarm grace_period_end for init_net only.
If nfsd was started from another net namespace lockd_up_net() calls set_grace_period() that adds lockd_manager into per-netns list and queues grace_period_end delayed work.
These action should be reverted in lockd_down_net(). Otherwise it can lead to double list_add on after restart nfsd in netns, and to use-after-free if non-disarmed delayed work will be executed after netns destroy.
Fixes: efda760fe95e ("lockd: fix lockd shutdown race") Cc: stable@vger.kernel.org Signed-off-by: Vasily Averin vvs@virtuozzo.com Signed-off-by: J. Bruce Fields bfields@redhat.com Cc: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/lockd/svc.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -274,6 +274,8 @@ static void lockd_down_net(struct svc_se if (ln->nlmsvc_users) { if (--ln->nlmsvc_users == 0) { nlm_shutdown_hosts_net(net); + cancel_delayed_work_sync(&ln->grace_period_end); + locks_end_grace(&ln->lockd_manager); svc_shutdown_net(serv, net); dprintk("lockd_down_net: per-net data destroyed; net=%p\n", net); }